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Comment by imgabe | Hacker News Reader

> A 2011 study by the U.K. government found a person would have to reuse a cotton tote bag 131 times before it was better for climate change than using a plastic grocery bag once.

This seems disingenuous. 131 uses of a cotton tote bag doesn't replace 1 plastic bag, it replaces at least 131 plastic bags, if not 2-3x that amount since the tote bags are bigger and sturdier and hold more.

I think the fundamental problem with plastic bags is that since they are 1 or 2 use, they are always going to be entering the environment at a rate faster than they degrade. So there is going to be an ever-increasing buildup of plastic bags in the environment for as long as they go on being used.

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Used once is referring to plastic bags used to hold groceries and then immediately thrown out. (Not used more than once: ie a garbage bag, pick up dog poop, etc)

So it is comparing 1 reusable bag used 131 times to 131 plastic bags.

Further in the article another study considers plastic bags used more than once, which are much better for the environment.

>I think the fundamental problem with plastic bags is that since they are 1 or 2 use, they are always going to be entering the environment at a rate faster than they degrade. So there is going to be an ever-increasing buildup of plastic bags in the environment for as long as they go on being used.

I think it is much more important to look at scientific studies than what a random person hypothesizes with no evidence to back it up.

> Used once is referring to plastic bags used to hold groceries and then immediately thrown out.

What percentage of people do this? We use them as “free” bags for garbage bins that we would otherwise have to buy, or for lunch where you won’t/can’t take an insulated bag (outing or when you won’t go home right after work).

How many garbage bags do you use per week? Just for myself I'd buy I guess ten bags of groceries a week and maybe three bags of trash a week. It doesn't add up.

When living with other people, we always accumulated huge numbers of saved plastic bags over the months. I'd recycle them but by myself I use reusable bags and a backpack that helps me carry them back. I get a handful of plastic bags every now and then when I get something without planning and those I put to use like you suggest.

We used to have a surplus of plastic bags before we started making a concerted effort to use cloth bags. (I don't know what they're actually made of, but they're designed for re-use.) Now, we actually run out of plastic bags that we used to use for various things like dog-poop (when we run out of smaller bags and forget to re-order), small bin liners, and general transportation needs. (Though for the latter, we almost always get to re-use the plastic bag again afterwards.)

So my answer is: For those who aren't recycling, I'd guess that most people throw bags out. For those who are, it's going to be a smaller number, depending on how hard they try to avoid plastic bags at the market.

Turn it around and see if this makes more sense: for the pollution caused by making one cotton bag you could have made 131 plastic bags. This means that if you fail to use your cotton bag 131 or more times, you've created more pollution than you have saved.

Why wouldn't you use it more times than that? They last years. That's ~2 years of weekly grocery trips. And each usage is going to replace 2-3 of the smaller, weaker plastic bags, maybe more.

Of course most people who purchase cotton bags intend to use them many times. The study that was quoted simply quantified how much reuse is required to make them worth it, and it turns out that this is a surprising number to many people. Plastic bags are really cheap, and growing cotton is more expensive than it would seem.

The problem we are talking about isn't the pollution creating the plastic bags but their disposal in the deep sea.

OK, lets run with that scenario.

I shop once a week, and normally fill 2-3 cotton bags. So I'd have paid off my pollution within a year. Maybe 6 months, as my cotton bags hold twice as much as plastic bags.

Also, not all production of bags is going to have the same level of pollution. We DIY many things in our home, and although we do buy the raw cloth, we sew them together ourselves. I suspect that drops the pollution somewhat.

In which case, I may be in a better place simply by using bags for a few months.

That doesn't sound so bad to me.

Somehow many of our cotton bags get lost probably well before they've seen 131 uses. :(

We keep ours in the trunk of our car. Makes it easy to do unplanned grocery shopping. Take them in, unpack, hang them on the doorknob to bring back to the car next time we go out. Haven't lost one yet, and we've had the same 5 for ~8 years.

But when you ban plastic bags, people still use plastic bags. They actually buy thicker plastic bags instead of reusing the grocery bags.

"What I found was that sales of garbage bags actually skyrocketed after plastic grocery bags were banned," she says. This was particularly the case for small, 4-gallon bags, which saw a 120 percent increase in sales after bans went into effect.

> they are always going to be entering the environment they'll end up in land fill or recycled? The environment will never see them, at the very least they will never end up in the sea...

If I recall correctly most of the plastic bags come from developing countries that do not dispose of any of their garbage properly anyway.

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